I'm looking over weapons in MgT and I think I see what's going on. No other basic slug thrower has intrinsic armor piercing. That sounds like that dense dart, along with high velocity, has the energy to punch very hard. As we have been discussing, that amount of power should translate to equivalent recoil. MgT has a Bulky trait the describes large or unwieldy OR high recoil. A few slug throwers such as the heavy revolver, shotguns in general, big game rifle and the heavy advanced combat rifle have that trait which would represent having a kickback. The gauss weapons, including the magrail weapons, don't. This sounds like gauss weapons do in fact by their physics reduce but don't eliminate recoil. It suffers the effects of zero g combat like any other normal slug thrower while still having kinetic damage ability combustion weapons can't match.

It suffers the effects of zero g combat like any other normal slug thrower while still having kinetic damage ability combustion weapons can't match.

This is an aspect i hadn’t considered when I posted the original question. Now that I understand the inherent recoil involved I’m inclined to keep Gauss weapons RAW. But i do still like the idea of variable power and I’m going to keep exploring that.

Recoil, if you think of the gauss weapon as "throwing" the rounds down range, rather than trying to wrap your head around pushing, or pulling the round, it might be simpler to visualize. as several people have indicated, force is being exerted, and produces recoil. On a larger weapon, I don't know why you couldn't justify a higher-tech grav-based stabilizer to reduce the recoil for practically any portable weapon. It's just a matter of inertial compensation at that point.

Reducing the muzzle velocity would quickly render the weapon useless. The high muzzle velocity is the primary factor in the effectiveness of the standard gauss weapon.
If you take a look at the description of Discarding Sabot ammunition in wikipedia, for instance, you'll see the low-tech, chemical attempt to put a small caliber penetrator on target at high speed. The Gauss weapon just skips the sabot and the powder charge and uses magnetic coils to throw what is essentially a hard, pointy, little rod (flechette) at the target.

I had a player in my campaign recently ask if he could purchase APDS rounds for his gauss pistol. I called it a silly thing and explained how APDS rounds work.

All that said, I have regions in my Traveller campaign where chemical weapons were almost completely replaced by Gauss weapons in a variety of configurations. I like a nice 15mm Hvy Gauss Pistol with HEAP rounds for blowing holes in vacc suits and combat armor, even Battle Dress if you're using Directed Plasma rounds.

Also, I don't understand why HEAP rounds are no longer a thing for Pistols, Rifles, or Shotguns (CSC pg 140)

Also, Concussion ammo should be available for shotguns, and have the burst trait.

It would have been nice if someone had given a little more thought to the alternate ammo types, their traits and TL availability. There seems to be some disconnects, or basic misunderstanding of several of the ammunition types.

I probably have read too much "Stainless Steel Rat". I like all flavors of Gauss weapons, and big Recoilless Pistols.

It seems reasonable that you could scale a "Gauss" weapon up to a sizeable bore, shotgun sized doesn't seem entirely unreasonable, and with a variable velocity, computer controlled Gauss "launcher", you could place various munitions at precise locations within several hundred meters.

We have rifle/scope combo's now that let you mark a target at extreme ranges and manage the firing when the barrel is properly aligned for pinpoint accuracy.

Interface that with a HUD in your combat helmet, and appropriate software in your computer weave, or weapon, warheads that communicate things like mass, cross-section, and aerodynamic profile to the weapon, and you've got a weapon system that provides unparalleled flexibility. Due to the ability to adjust the muzzle velocity for each shot, perhaps even putting some "english" on the round by adjusting spin, automatic calculation of, and adjustments for. atmospheric conditions, elevations, and rotating reference frames (planetary rotation, and inside rotating space stations, or other scenarios) you can use the weapon in both direct, and indirect, fire scenarios with frightening accuracy.

Like the US Military's new SAW, you can have your shrapnel producing warhead fly 200 meters, clear the window frame by 3 feet, then explode, affecting the two shooters ducking inside a window in a distant building. The difference is that you can now arc your round in, or use a smart round, launch it to 1000m altitude, then let it find its target from there without exposing yourself, or your position.

Checking out TNE's Fire, Fusion and Steel which has a extensive system for creating gauss and mass driver weapons. There's information on the helical barrel that drives the munition. Interesting note, 'One advantage of the tremendous torque generated by the rapid discharge of the [homopolar generator] is that it can be used to gyroscopically counter part of the weapon's powerful recoil.'. As to munitions, they can have any caliber in millimeters up to 20mm and the length of the finned dart is the diameter multiplied by 5 while weight is .02 times 3.1416 times radius in mm of the bullet. The bullet can be solid, HE, HEAP or Tranq. Gauss weapons can have gyroscopic compensators or inertial compensators at higher TLs. The IC is a harness worn by the user and the weapon is attached.

The sound from a gauss gun is the bullet's supersonic velocity and the gun is treated as having sound suppressors. The muzzle velocity can be designed to fire a bullet at subsonic and be considered a silenced weapon.

Because gauss creates virtually no barrel heat, it can fire large number of rounds without multiple barrels plus gauss muzzle velocities can be up to 6000 meters per second though often range no less that 1500 m/s or no more than 4000m/s.

Not convinced that a real-world gauss weapon would create virtually no heat. Even if the coils are super-conducting (almost certain) other components in the system probably won’t be and the cycling of the intense magnetic fields involved in those parts will generate heat. The air inside will heat up from friction but that’s likely a lesser effect. There may also be a military requirement to minimize EM signature; that shielding/ screening may warm up over time as well.

Having said that, it’s likely to yield far less heat than a traditional slug thrower.

Not convinced that a real-world gauss weapon would create virtually no heat. Even if the coils are super-conducting (almost certain) other components in the system probably won’t be and the cycling of the intense magnetic fields involved in those parts will generate heat. The air inside will heat up from friction but that’s likely a lesser effect. There may also be a military requirement to minimize EM signature; that shielding/ screening may warm up over time as well.

Having said that, it’s likely to yield far less heat than a traditional slug thrower.

If you have room temperature superconductors you wouldn't have a lot barrel heat, but, you're right, you would have heat in the system.

The original VRF Gauss Gun (CT Mercenary) was cryogenically cooled, but unless you wanted to do some more calculations, you could hand-wave most Gauss small arms wouldn't generate enough heat to be a problem. Man-Portable support weapons would likely require some minimal cooling, perhaps a chilling unit, or heat-sink, built into each drum of ammo.

It's implied it's a slug, but a gauss bullet could be a fletchette to ensure stability.

It's basically the Vietnam era M193 ball bullet, as described in the original Mercenary.

Mercenary says:
"Gauss Rifle: The ultimate development of the slug thrower, the gauss rifle generates an electromagnetic field along the length of the barrel which accelerates a 4 mm, 4 gram needle bullet to velocities of 1500 meters per second. The round itself consists of a dense armor piercing core surrounded by a softer metal covering, ending in a hollow point, giving the round both high stopping power and a good armor piercing capability. Flight along the barrel is nearly frictionless, with spin stabilization imparted through magnetic bias."

Hasn't it been described as having a 10:1 aspect ratio? Didn't Marc Miller, or Loren write about a conversation on a plane with a ballistics guy from DARPA who said that there were designs for a wasp-waisted hypersonic flechette that was virtually silent? I have a vague recollection of reading that sometime in the last 40 years. Can anyone confirm, and source it, or am I imagining it?